wickers

I just purchased a secondhand plane and I need help with it. Does anyone know who makes the mahoney 125 engine or anything about it. None of the hobby shops where I live know about it either. Also does anybody know about the challenger 720 transmitter. any help will be appreciated.

Charley

My Feedback: (2)

The Maloney 125 was originally sold by World Engines/Indy RC. It reportedly made a good paper weight; ran OK, not much power.

The Challenger 720 transmitter is a 7 channel FM unit that was sold by Polk's Hobbies under the Aristo-Craft brand name. It's a good narrow band xmitter with lots of analog mixes and servo reversing on all channels. It also has a plug-in RF module. It was pretty much the top of the line Hi-Tec xmitter of the day, grand-daddy of the present Hitec radios. The 7-channel World Engines xmitter was also made by Hi-Tec in the same factory, on parallel assembly lines. The WE xmitter differed from the Challenger only in the color of the case and that the user had to remove the backplate to change the RF module. The Aristo dual-conversion receivers weren't as bullet proof as today's units. I remember having trouble with TV channel 4 when I used channel 24.

I'm still using a 720 Xmitter on chan 18 with a Futaba flite pack and have other RF modules on chans 20 & 24. I also have one of the WE xmitters that works but has a broken rudder gimbal. Wish I could find another gimbal.

These two radios were the first narrow band FM radios readily available in the USA. I bought one of each and loads of extra servos and receivers. Flew them a lot.

One other thing. Both xmitters use a 9-cell 10.8 volt battery instead of the 8-cell 9.6 volt that's commonplace.

Cheers,

CR

wickers

Thanks for the help charley. I have been told on here that the challenger 720 is now illegal to use. Is this true or have I been mislead. I will probably run the engine til I can afford a new one or til it gives out , whichever comes first. Also do you still have the manual that came with your 720 or do you know if I can get it anywhere. I've checked the net but without reward.

Hobbsy

My Feedback: (102)

Wick, the Maloney should turn a 15x8 at 7,200 and will run forever on a small amount of gas. It is better than people give it credit. It has needle bearings on the rod so doesn't need much oil in the gas. A 16x6 will work well on it too but John Maloney did all the testing on it with a 15x8. The mag is weak so must be started with a starter.

wickers

I am new to the plane scene what is a 15x8. What fuel to oil ratio would you suggest? Also what type oil should I use? Any help will be great.

Charley

My Feedback: (2)

It's legal, the guy was mistaken. I have the manual here in my hot little hands. I just went to look for it. Send me your adress and I'll get a copy in the mail.

Cheers,

CR

Ekelfekin

Hello Charley and others
"Help required number two."

I was doing a search for "challenger 720" and was directed to this discussion board.
I had to join up it looks so interesting.

Would there be any chance of getting a copy of the information on this 720. I have one of these units I purchased in Australia in 1990 (36.095Mhz FM).
It is 7 channel but sold with only 4 servos.
But I need information on mixing the channels.
Any help would be really neat.

Thank you
"Ekelfekin"
Sandy Johnston
AK NZ

bobertperry

if you would not mind would you send me the manual or explain how to have flaps with this controller. I bet i can figure it out but it would nice if someone would share how exactly to and what channels to use

FreakyFlier

My Feedback: (1)

Wickers, A 15x8 prop is one that is 15 inches long with 8 degrees of pitch. The bigger the prop or the more pitch, the faster it will pull you through the air. You can't just stick on a bigger prop (length or pitch). You need to know what the engine can handle or "turn". You do not want the engine overloaded and struggling. You also do not want to put on a prop that is too small. You will over rev and damage the engine. I am not familiar with your engine so take the previous advice and keep an eye on the engine. Go up or down on the prop to adjust your rpm's into the appropriate range. Be careful when using a longer prop, watch for ground clearance and your fingers.
Keep in mind!! This is over simplified. You need to start with the recommended prop then experiment. Some prop combo's give speed some give more torque, etc.